Coral Bleaching

Coral bleaching is a process in which the coral loses his photosynthesis algae called “zooxanthellae”. That process can be also caused by the loss of the pigments of the algae that give color to the coral. Due to this factor, the coral became translucent, making it possible for us to observe the calcium carbonate skeleton of the animal. This is why this problem is known by the name “coral bleaching”. We can say that the main factor that causes it, is the increases in the water temperature in the oceans. This event can be either transitory or mortal to the corals.

Subtitle: 1: Healthy coral: the coral and the algae lives in symbioses

2: Stressful Coral: Over stress, the coral expels the algae

3:Without the algae, the coral became white and vulnerable

Coral Bleaching and global warming

Throughout the studies of the theme, was noticed that the abrupt change in the ocean’s temperature has a direct association with the phenomenon, that occurs due to the fact that unlikely the seasonal changes (as, for example, El Niño), the temperature levels don’t normalize in a determined period of time, which ended permanently expelling the zooxanthellae of the corals “skin”. Furthermore, the temperature increase also contributes to the acidification of the water, which difficult the incorporation of the calcium carbonate harder for the corals

Can a coral "recover" from the bleaching?

In some cases, yes it can. But only if the water conditions go back to normal, and the coral receives again the algae, if that happens, the coral will have his color back and survive. However, if the water temperature or what we call “stressing factors”, for example, the poor water condition, don't normalize, the coral will go through a delicate estate, which, it may not resist.

It takes decades for a coral reef recover from a bleaching event, that's the main reason that is vital that it doesn't occur with frequency.

The impact caused by the destruction of the Great coral barrier.

Another important point is the constant destruction of the Great coral reef in Australia. More than 93% of this ecosystem suffers from the coral bleaching, according to the World Wildlife Fund (WWF), about 1.500 species of fishes, 3 thousand of mollusk, and 215 types of birds-without mention the marine turtles, sponges, anemones and others- are directly dependent of the existence of the Great Barrier.

Is worth saying that in the same way, is estimate that half a million people are benefited directly or indirectly from the productivity and preservation of the barrier.

Studies arise that the global costs of the degradation of the coral’s reefs can cost about US $20 billion (if happens moderate bleaching), US $84 billion (if happens severe bleaching) in 50 years. The losses on the tourism industry will be principally affected ($10 billion - $ 40 billion of injury), followed by the fishing activities ($7.0 billion - $23.0 billion) and biodiversity ($6 billion - $ 22 billion).

The impact in fishes communities.

Almost everything in the reefs has a dependency on the corals.

Scientists found out that ecological impacts with relations to the decline of corals numbers can generate negative impacts in the fishes communities. A studie from New Guinea, for example, has shown that the decline of a species of fish in a determined area was directly related to the decline of the corals that has an association with the specie. Furthermore, suggest that the youngest fishes prefer to move to areas with more corals. Likely results were found in the Great Barrier.

Organizations and projects to support

1. Great Barrier Reaf Legacie: A non-governmental institution with research projects, environmental education, that looks forward to “reforest” the Great Coral Reef. The project accepts donations.

2. Wild Foundation: Developers of the "chasing corals" project (they have a documentary available on Netflix as well) willing to show the coral bleaching. How can I help? The project accepts donations, is possible to shop in their online store, or become a member.

3. Seascape Caribbean: The marine biologist Andrew Ross company, which is responsible to reintroduce corals in the sea.

References:

• Cesar, H.J.S., L. Burke, and L. Pet-Soede. 2003: The Economics of Worldwide Coral Reef Degradation. Cesar Environmental Economics Consulting, Arnhem, and WWF-Netherlands, Zeist, The Netherlands. 23pp (pdf, 1.4M)

• Booth, D.J. and G.A. Beretta. 2002: Changes in a fish assemblage after a coral bleaching event. Marine Ecology Progress Series 245: 205-212. (Website)

• Chasing Corals (website)

• World WIldlife Found (WWF) website

• BUCHHEIM, JASON. Coral Reef Bleaching. Marinebiology.org. Disponível em: <https://www.marinebiology.org/coralbleaching.htm>. Acesso em: 07 jul. 2019.

• What is Coral Bleaching and What Causes It - Fight For Our Reef. Australian Marine Conservation Society. Disponível em: <https://www.marineconservation.org.au/coral-bleaching/>. Acesso em: 07 jul. 2019.